Substrate Etching Selectivity via Radical-Mixed Unit Cycles
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Solution Overview
Problem
Current methods for etching processes in semiconductor manufacturing face challenges in achieving high selectivity between silicon oxide and silicon nitride films, which is crucial for advanced semiconductor and display element production.
Innovation Solution
A method and apparatus that utilize a unit cycle involving the supply of radicals from a first treatment gas mixed with a second treatment gas to a substrate, where the substrate treatment step is controlled to only react with the silicon oxide film before significantly reacting with the silicon nitride film, generating a solid by-product like (NH4)2SiF6 and sublimating it in a heated atmosphere, while using an ion blocker to filter ions and electrons, ensuring high etching selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to etch silicon oxide film, then etching process can be performed, but etching selectivity between silicon oxide film and silicon nitride film is insufficient
Solution Approach 1:
The etching process is divided into multiple unit cycles, each consisting of a substrate treatment step and a by-product removal step. This segmentation allows precise control of the etching reaction time, enabling selective removal of silicon oxide film while preventing etching of silicon nitride film.
Solution Approach 2:
The etching process uses periodic alternating supply of first treatment gas (containing fluorine radicals for etching) and second treatment gas (for by-product removal). This periodic action enables controlled etching of silicon oxide film while allowing recovery periods that prevent damage to silicon nitride film.
2Productivity
If reaction gas is supplied continuously to maintain etching rate, then productivity is improved, but selectivity between different films deteriorates
Solution Approach 1:
The process alternates between etching phases (supplying first treatment gas with fluorine radicals) and cleaning phases (supplying second treatment gas). This periodic action maintains high etching rates during etching phases while preventing selectivity loss through controlled reaction timing.
Solution Approach 2:
The substrate temperature is pre-heated to a specific range (50-150°C) before etching begins. This preliminary heating ensures that by-products can be effectively removed in subsequent steps, maintaining high selectivity throughout the etching process.
3Productivity
If high density plasma is used to increase etching speed, then productivity improves, but control precision over reaction timing deteriorates
Solution Approach 1:
A showerhead is introduced as an intermediary component between the plasma generation region and the substrate. The showerhead distributes radicals uniformly and provides a controlled interface for gas supply, enabling precise timing control even with high-density plasma.
Solution Approach 2:
The process monitors and controls the timing and duration of gas supply phases to maintain optimal etching conditions. By controlling the unit cycle timing and gas flow rates, the system achieves precise reaction timing control while maintaining high etching speeds.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly enhances etching selectivity between silicon oxide and silicon nitride films, allowing for precise etching of silicon oxide without substantially etching silicon nitride, thereby improving manufacturing processes for semiconductor and display elements.
Implementation Method 1
a plasma source unit for applying a power to excite the first treatment gas supplied to the plasma chamber into a plasma state
Implementation Method 2
supplying a reaction gas in which radicals constituting plasma of a first treatment gas are mixed with a second treatment gas onto the substrate
Implementation Method 3
an ion blocker provided between the plasma chamber and the process chamber, and through which radicals constituting plasma of the first treatment gas selectively pass downward
Implementation Method 4
sublimating the solid by-product in a temperature atmosphere of the substrate that is heated
Data Source
AI summary
According to one aspect of the present invention, a method of treating a substrate within a chamber includes performing a unit cycle at least one time, in which the unit cycle includes a substrate treatment step of supplying a reaction gas in which radicals constituting plasma of a first treatment gas are mixed with a second treatment gas onto the substrate, wherein the substrate includes a first thin film, and a second thin film having a lower reactivity to the reaction gas than the first thin film.